Straight lift pumping unit



Sept. 13,1938.

Filed Feb. 16, 1937 Q QN Q N n V41 w A mw fm Q h m )K Ml lmWEyIVL .WN MW Pwmxm Q\\ m Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE STRAIGHT LIFT PUMI'ING UNIT Christopher G. Hopkins, Nashville, Tenn.

Application February 16, 1937, SerialNo. 126,058

11 Claims.

This invention relates to lift pumps for pumping oil, gas and analogous uses, and is particularly concerned with pumps generally classed as of the walking beam straight line lift type.

Various types of linkage mechanism have'been devised for imparting a supposedly straightline movement to the polish rod of a lift pump, or for converting the arcuate movement of the walking beam into rectilinear movement. There are certain objectionable features to known mechanisms of this type. The linkage mechanism is not only complicated in most instances, but actual experience shows that the supposedly rectilinear movement is not in fact true, and that the polish rod is being wobbled or slightly bent dfuring the pumpingoperation. This may not be in evidence until after the pump has been in use for some time, but eventually it shows up through wear on the polish rod and bearings and looseness of the coacting parts. In a number of instances, the complicated system of linkage mechanism is not sufciently rigid and strong to give the desired life to the pumping unit.

The primary object of the invention, therefore, is to provide a pumping unit of the straight line lift type wherein the arcuate movement imparted to the walking beam is converted into true rectilinear movement, thereby giving a true straight line action to the polish rod, and to accomplish this desired result with mechanism of a simplified type.

Another object is to provide a straight line lift pump unit wherein the mechanism for converting arcuate into straight line motion is not only of' a simplied type but embodies relatively great strength and is capable of long life with a minimum of Wear on the coacting parts.

Another object of the invention is to provide a straight line lift pump unit embodying a particularly advantageous type of straight line toggle linkage mechanism which in addition to imparting a true straight line movement to the polish rod serves to brace the walking beam against a tendency toward rotation in a horizontal plane.

The foregoing and other objects and advantages will become apparent in View of the following description taken in conjunction with the drawing, wherein:

Fig. 1 is a View in side elevation of a lift pump embodying the features of the present invention.

Figs. 2 and 3 are, respectively, horizontal and vertical sectional views taken substantially on the lines 2 2 and 3--3 of Fig. 1.

Fig. 4l is a diagrammatic representation of the action of the improved lift pump.

Generally speaking, the runit consists of a main stationary frame structure herein termed a. main or stationary Samson post having mounted on the upper extremity thereof an. arcuatelymovable Samson post by means of which the walking or rocking beam is given a floating mounting. The movable Samson post and walking beam have connected thereto a particular arrangement L@ of toggle linkage whereby the conversion of rortary into straight line movement is carried out.

Referring in detail to the drawing, the numeral 5 indicates a base on which is disposed the stationary frame structure or main Samson post, generally indicated at B. Asshown the stationary Samson post is made up of skeleton framework, and at the upper extremity thereof theV framework is extended horizontally outward. To provide for this extension, side beams 1 are 2.o rigidly connected to the upper end of the iramework 6 and converge inwardly, as attic,` and at their ends are constructed to provide a link shaft bearing as at 8.

Approximately inthe axially central portion of the Samson post 6 is mounted a supplemental Samson post or beam supporting Vmember 9, which at its lower end is pivotally supported on a shaft I0. A rocking or walking beam II is pivotally mounted on the upper end of the movable post 9 through the mediumvof a bearing block or shoe IIa. Since the post 9 Vis permitted to swing arcuately on shaft I Il and since the beam I I is permitted a like movement on saidzpost, the beam is given a floating support or mounting on the main stationary Samson post or-framework 6.

At one end said beam i's'provided-with a bearing bracket I2 which is pivotally connected to the polish or lift rod I3 of a well pump, the latter not being shown in the drawing since its par- 40 ticular construction formsno'part of the present invention. At its opposite end, the beam II isoperatively connected with a drive unit I4 through the medium of aV connecting rod I5;

Toggle mechanism comprising horizontal links I6, I'I and vertical link I8 is provided. Links I6 are pivotally connected at one end to the post 9 throughthe medium of a shaft I9 and atvthe opposite end thereof to the linkn I'I through the medium of a shaft-2D. Link I'I at its-outer end is 50 pivotally anchored to the frameextension 'Ia through themedium of the member 8. Link I8 at its upper end is provided with a pivoted bearing block 2l which is secured to the walking beam II, and at its lower end has bearing on shaftZIl,

the latter serving as a common connection for the inner ends of the respective links.

In operation, assuming that the first movement of the connecting rod I will be an upward thrust from the position shown in Fig. 1 and that the polish rod is to be given a downward stroke. The thrust of the connecting rod I5 will have a tendency to move the stroke end of beam I I arcuately, but this tendency is resisted by the links I6 and I1 which at this time lie straight or, as shown, in a horizontal plane. The movement of the beam end Will therefore be straight downward, and as the restraining links I'B and I1 break and move downwardly, the beam will float outwardly and its end continue to move downwardly. It will thus be seen that the post 9 rotates through a controlled and predetermined arc governed by the links I6 and I1, the end of the beam which is connected to the polish rod I3 movingin atrue vertical, line. The same operation holds true throughout 'the full upward and downward stroke of the beam II.

A check may be made on the foregoing description Vof operation by referring to the diagram in Fig. 4 in conjunction with the following trigonometric calculation:

Let a=any angular movement of Iwalking beam Then D=LL cos a And D/2=2a:-2a: cos a Therefore zc=L/4 for any position and A moves in a true vertical line.

The foregoing calculation assumes that the combined lengths of the links I6 and I'I, or the distance between axes of I9' and 8, equals onehalf ,the distance between theaxes of IIa and I2 and that the pivotal axis ofV I9 lies midway between AIII and IIa. t Y n I It should be noted, however, that it is not nec'- essary toy locate pivot point I9 midway of pivot points IIJ and IIa. If for any reason it should be desired to locate I9 nearer to I0, for example, than Ato I Ia, links I6, I1 and I8 may be lengthened tor compensate for such`change. Accordingly D/2 becomes a variable factor and may be substituted by K. We then have:

Then K.L (1-cos a) =2rc (1-cos a) and K.L=2:1,`

KL fb? It will be noted that the angle generated due to the angular travel of the walking beam is the same as that of the links I6 and I1, and that the respective lengths of the said links are the same. Thus if the movable post 9 and links I6, I1 and I 8 together with the walking beam I l are initially set or arranged so that the said post lies'in a true" vertical plane, the polish rod connected to thevone end of said beam must always be actuated `in a plane whose axis lies parallel to the initial vertical'axis of said post.

By checking the diagrammatic illustration in Fig. 4, it will be notedfthat the quadrilateral defined by the links I6 and I8 and the portions of the Walking beam and movable post 9 which lie between the-pivotal points 2I--I la and II a--IB constitutes a parallelogram. Thus there are certainA parts which must bear a denite or fixed relation to one another; pivot points IIa, 2| and I2 should lie in the same horizontal plane and I Ia,

I9 and IIJ in the same vertical plane, and links IB and I'I should be of the same length. However, the length of the floating Samson post 9 does not have to bear any definite or fixed relation to the length of the walking beam. Obviously, the longer it is made, the less will be its deviation from a vertical plane while in operation. However, if the length of the post 9 is increased to too great an extent, manufacturing costs as well as transportation and assembly cost would be increased. For most practical purposes, the relative dimensions shown in the drawing will prove satisfactory.

In operation, the strain on the pivots or bearings of the links I6 and Il increases in proportion to the deviation of said links. However, if the proportions illustrated in the drawing are substantially adhered to, the maximum deviation of thelinks I6 and I'I from a horizontal plane would be approximately fourteen degrees, which has very little effect on the mechanical efficiency of the apparatus while in operation.

The arrangement herein disclosed is strong and rugged and may be adapted to both heavy duty and light service and yet at the same time, it is simple in construction and involves relatively few moving parts.

It will also be noted that the horizontally extended frame structure having the linkage connected thereto in the manner shown braces the walking beam II against any tendency to swing or oscillate ina horizontal arc, thereby overcoming wobbling due to such action.

It will be readily understood that certain variations in structure and design may be adopted within the scope of the invention as dened by the appended claims.

I claim:

l. In a pumping unit, a walking beam, a movable support providing a oating mounting for said beam, a stationary upright frame for said support, and means for converting the arcuate movement of said beam into rectilinear movement at the pump-operating end thereof comprising linkage mechanism connected in toggle relation on a common pivotalaxis, said mechanism including opposed links arranged substantially horizontally with their ends remote from said axis pivoted respectively to the support and frame and an intermediate link having its remote end pivotally connected to the said beam.

2. In apumping unit, a stationary support, a walking beam, a movable Samson post mounted on said support and providing a floating mounting for said beam, and means for converting the arcuate movement of said beam into rectilinear movement at the pump-operating end thereof comprising linkage mechanism connected in toggle relation on a common pivotal axis, said mechanism including opposed horizontal links having their ends remote from said axis pivoted respectively to the post and frame and an intermediate vertical link having its remote end pivotally connected to the said beam, said links being of such relative lengths that the angular travel of the restraining links is the same as that of the walking beam.

3. In a pumping unit, a main stationary frame structure or Samson post, a movable Samson post pivotally mounted on said main Samson post, a Walking beam pivotally mounted on said movable VSamson post, and means for converting the arcuate movement of said beam into rectilinear movement at the pump-operating end thereof comprising a plurality of restraining links connected in T-shaped toggle relation, including opposed links pivotally connected respectively to the movable Samson post and the stationary Samson post and an intermediate link arranged substantially perpendicularly to said opposed links and pivotally connected to said beam.

4. Ina pumping unit, a main stationary Samson post, an arcuately movable Samson post pivotally mounted on said stationary Samson post, a walking beam mounted on said movable Samson post for arcuate movement in a plane parallel to the plane of movement of said latter post, and means for converting the arcuate movement of said beam into rectilinear movement at the pump-operating end thereof comprising a plurality of restraining links connected in toggle relation including opposed links arranged substantially horizontally, the outer end of one of the horizontal links being pivoted to said movable Samson post and the outer end of the other horizontal link beinCf pivotally anchored to said stationary Samson post, and an intermediate link arranged substantially perpendicularly to the horizontal links and having its upper or outer end pivotally connected to said bea-m.

5. In a pumping unit, a main stationary Samson post, an arcuately movable Samson post pivotally mounted on said stationary Samson post, a Walking beam mounted on said movable Samson post for arcuate movement in a plane parallel to the plane of movement of said latter post, and means for converting the arcuate movement or" said beam into rectilinear movement at the pump-operating end thereof comprising a plurality of restraining links connected in toggle relation and including opposed links arranged substantially horizontally, the outer end of one of the horizontal links being pivoted to said movable Samson post and the outer end of the other horizontal link being pivotally anchored to said stationary Samson post, and an intermediate link arranged substantially perpendicularly to the horizontal links and having its upper or outer end pivotally connected to said beam, said opposed links being of substantially the same length.

6. In a pumping unit, a fixed Samson post, an arcuately movable Samson post mounted on the upper end of said xed posta walking beam pivotally mounted on said movable Samson post, a pair of horizontal restraining links pivotally connected at their inner ends to a common axis and at their outer ends pivotally, respectively, to the xed Samson post and the movable Samson post, and a third link arranged perpendicularly to horizontal links and having its lower end pivotally connected to said axis and its upper end connected to said beam.

7. In a pumping unit, a ixed Samson post, an arcuately movable Samson post mounted on the upper end of said i'lxed post, a walking beam pivotally mounted at an intermediate point on said movable Samson post, means operatively connected to one end of said beam for imparting a rocking movement thereto, the opposite end of said beam having an operative connection with the polish rod of a pump unit, and means for converting the arcuate movement of said beam into rectilinear movement at the point of its connection with the polish rod comprising a plurality of restraining links connected in toggle relation on a common pivotal axis and including opposed links pivoted respectively at their outer ends to the movable Samson post and the fixed Samson post and an intermediate link pivotally connected to said beam.

8. In a pumping unit, a xed Samson post, an arcuately movable Samson post mounted on the upper end of said xed post, a Walking beam pivotally mounted at an intermediate point on said movable Samson post, means operatively connected to one end of said beam for imparting a rocking movement thereto, the opposite end of said beam having an operative connection with the polish rod of a pump unit, and means for converting the arcuate movement of said beam into rectilinear movement at the point of its connection with the polish rod comprising a plurality of restraining links connected in toggle relation on a common pivotal axis and including opposed links pivoted respectively at their outer ends to the movable Samson post and the fixed Samson post and an intermediate link pivotally connected to said beam, said opposed links when `in a neutral position lying in substantially a horizontal plane with the intermediate link arranged perpendicularly thereto.

9. In a pumping unit, a main stationary frame structure or Samson post, a movable Samson post pivotally mounted on said main Samson post, a Walking beam pivotally mounted on said movable Samson post, and means for converting the arcuate movement of said beam into rectilinear movement at the pump operating end thereof comprising a plurality of restraining links connected in toggle relation, and including opposed links pivotally connected at their outer ends respectively to the main Samson post and. the movable Samson post and an intermediate link pivotally connected at its upper end to said beam, a parallelogram being defined by the intermediate link, that portion of the walln'ng beam which lies between its pivotal connection with the intermediate link and the movable Samson post, that portion of the Samson post Which lies between its pivotal connection with the Walking beam and the adjacent toggle link, and said latter v link.

10. In a pumping unit, a main stationary frame structure or Samson post, a movable Samson post pivotally mounted at its lower end on said stationary Samson post, a walking beam pivotally mounted on the upper end of said movable Samson post, a plurality of restraining links connected in toggle relation including opposed links pivotally connected at their outer ends respectively to the stationary Samson post and the movable Samson .post and an intermediate link pivotally connected at its upper end to said beam, and a polish rod having a pivotal connection with the pump operating end of said walking beam, the pivotal connection of the upper ends of the movable Samson post, the intermediate link of the toggle and the polish rod lying in the same horizontal plane, and the pivotal connections of the movable Samson post with the walking beam, the adjacent toggle link and the stationary Sarnson post lying in the same vertical plane.

1l. In a pumping unit, a main stationary frame structure or Samson post, a movable Samson post pivotally mounted on said main Samson post, a walking beam pivotally mounted on said movable Samson post, and means for converting the arcuate movement of said beam into rectilinear movement at the pump operating end thereof comprising a plurality of restraining links connected in toggle relation, and including opposed links pivotally connected at their` outer ends respectively to the main Samson post and the movable Samson post and an intermediate link pivotally connected at its upper end to said beam,

Walkingr beam and the adjacent toggle link, and said latter link, and the pivotal connections of the movable Samson post with the walking beam, the adjacent toggle link and the stationary Samson post lying in the same vertical plane.

CHRISTOPHER G. HOPICINS. 

